1. Field of the Invention
The present invention relates to a label printing apparatus for printing labels, which are temporarily adhered in series to a web of backing paper, and for then winding the labels onto a label holder detachably mounted on the printing apparatus.
2. Description of the Prior Art
Label printing and applying apparatus are used in supermarkets, shops or the like. They are either nonportable, e.g. desk or table type, or they are portable types, as their intended uses dictate.
Generally, all the desk type apparatus are electrically powered, and they are roughly classified into two kinds. In one kind, a number of labels are arranged in series on their backing paper web, are continuously printed and are fed out in series to the exit from the apparatus, while still temporarily adhered to their backing paper web.
In the other kind of desk type apparatus, an electronic type, weighing, human readable character printer for weighing meat, fish, vegetables, or the like, and for printing and delaminating labels, is combined with an electronic bar code (for POS) printer for printing and delaminating labels. When an article is placed on a weighing pan, the two printers, i.e., the weighing, human readable character printer and the electronic bar code printer, print the two respective labels on the respective backing paper webs, separately printing human readable characters and bar codes in response to the electric signals coming from the weighing balance. The respective backing paper webs corresponding to the printed labels are turned at acute angles so that the printed labels are delaminated from the respective backing paper webs and the labels and the backing paper exit separately at two exits. The one label then at the exit from the human readable character printer is manually pinched and applied to the surface of an article, whereas the bar code label arranged at the exit of the bar code printer has its adhesive side applied and adhered to the back of the aforementioned article.
However, it is remarkably inefficient to manually bring the articles individually in the aforementioned manner to the bar code labels, and it is difficult to apply these bar code labels at desired positions. As a result, the desk type apparatus, which is combined with that weighing balance, is not used near the display shelves in shops, such as the supermarkets, because it is not suitable for such use.
In order to display commodities bearing printed labels on the display shelves of shops, therefore, currently only the other kind of apparatus is used, i.e., the desk type apparatus from which a number of labels printed in series are fed, while they are temporarily adhered to the backing paper web. Moreover, in applying the labels, which are printed by such apparatus, to commodities, a number of employees in the rear area of the shop peel the individual labels with their fingers, for a long time before the commodities are displayed at a counter, i.e., either before the shop is opened or after the shop is closed. Since the labels are applied manually by the workers, the speed of applying the labels to the commodities is usually as low as about 10 to 20 sheets per minute, producing poor working efficiency. In contrast, the label applying speed is about 100 sheets per minute for a hand labeler, which is capable of continuously applying the labels. At the same time, since the imprints on the labels are rubbed by the workers' fingers during label applying, the printed surfaces are often blotted and become hard to read.
The manual and portable type label printing and applying apparatus (called a "hand labeler") for printing and applying labels to articles is widely used mainly at the shop counter for label printing and applying purposes. Since this hand labeler is constructed so that the label printing and feeding operations are performed by repeated squeezing and releasing of the hand lever, the workers become tired. Moreover, since loud sounds are generated from the type surfaces of the printing head and from the platen which receives the types, the noises may raise a problem for some shops. Especially in a printing head for printing POS bar codes, strict accuracy is required for the width and spacing of the bar codes because these bar codes have to be read out by means of an optical reader. Nevertheless, due to a constructional error in the printing head and due to an excess or a shortage of the ink applied to the type surfaces, the bar codes are often neither accurately printed nor correctly read out. Furthermore, the bar code printing head necessarily is larger than the usual letter printing head because of the standardized size of the bar codes. As a result, the size and weight of the hand labeler are increased which fatigues the workers. At the same time, since bar code prints are difficult to understand by general workers, in contrast with numerals or letters, the bar code labels printed for one commodity are often erroneously applied to others. Although the bar codes require check digits, furthermore, the hand labeler is usually not able to be furnished with a function to automatically calculate the check digits, due to the limits in its size and construction. Therefore, the check digits have to be disadvantageously calculated in a separate manner and to be set in the printing head.
Therefore, label printing and applying apparatus according to the prior art, both desk or portable type, present a variety of problems, which should be solved, especially as the POS system comes into general use.